scholarly journals Comparisons of Different Methods to Determine Starting Altitudes for Dry Air Atmosphere by GNSS-RO Data

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1276
Author(s):  
Andrea Andrisani ◽  
Francesco Vespe
Keyword(s):  
Water Vapor ◽  
Water Vapor Pressure ◽  
Low Earth Orbit ◽  
Navigation Systems ◽  
Bending Angle ◽  
Dry Air ◽  
Air Atmosphere ◽  
Air Layers ◽  
Correct Application

Boundary profile evaluation (BPV) is an approach proposed in order to estimate water vapor content in the atmosphere. It exploits radio occultation (RO) observations of the signals emitted by the satellites of global navigation systems (GNSS) which are eclipsing (rising) as viewed by a low earth orbit satellite (LEO). BPV requires, as a preliminary step, the estimation of the dry background atmosphere model of refractivity (i.e., obtained from bending angle profiles) to be subtracted from the real observations in order to extract water vapor profiles. The determination of the lowest layer of the atmosphere over which the concentration of water vapor can be deemed negligible is particularly crucial for a correct application of the BPV method. In this study, we have applied three methods to set the starting altitudes for the dry air layers of the atmosphere: (1) by air temperature below some threshold values (for example, 250 K); (2) by “smooth” bending angle profiles in ROs; (3) by saturated water vapor pressure. These methods were tested with thermodynamic and bending angle profiles from 912 radiosonde excursions colocated with RO observations. For every dry air starting altitude we determined the best estimator from each of the three methods. In particular, by comparing those estimators with the quantiles and momenta of the dry air starting altitude distributions, we achieved improvements of up to 50% of the humidity profiles.

scholarly journals Determination of the Odour Adsorption Behaviour of Wool

2020 ◽  
Vol 3 (1) ◽  
pp. 30-39
Author(s):  
Ebru Yilmaz ◽  
Pinar Celik ◽  
Aysegul Korlu ◽  
Saadet Yapar
Keyword(s):  
Acetic Acid ◽  
Water Vapor ◽  
Adsorption Capacity ◽  
Weight Increase ◽  
Adsorption Behaviour ◽  
Dry Air ◽  
Adsorbed Amount ◽  
Dynamic Experiments ◽  
Adsorption Desorption

In this study, the adsorption/desorption behaviours of water vapor on wool, as well as of the redolents, such as acetic acid and benzaldehyde, have been investigated. For this purpose, static and dynamic experiments were carried out. Static experiments were conducted to model stagnant environments. In the experiments, wool came into contact with the material to be adsorbed or dry air and the weight increase/decrease was recorded for a certain period of time. The results obtained showed that the wool adsorbed the benzaldehyde very little, whereas the adsorbed amount and the rate were abundantly increased for acetic acid under the same conditions. From these findings, the adsorption capacity of wool for the redolents was tentatively ranked in accordance with their adsorbed amounts as acetic acid>water>benzaldehyde.

Development of a quasi-adiabatic calorimeter for the determination of the water vapor pressure curve

2012 ◽  
Vol 83 (7) ◽  
pp. 075114 ◽  
Author(s):  
S. Mokdad ◽  
E. Georgin ◽  
Y. Hermier ◽  
F. Sparasci ◽  
M. Himbert
Keyword(s):  
Water Vapor ◽  
Vapor Pressure ◽  
Water Vapor Pressure ◽  
Adiabatic Calorimeter ◽  
Pressure Curve ◽  
Vapor Pressure Curve

Multiyear Observations of the Tropical Atlantic Atmosphere: Multidisciplinary Applications of the NOAA Aerosols and Ocean Science Expeditions

2011 ◽  
Vol 92 (6) ◽  
pp. 765-789 ◽  
Author(s):  
Nicholas R. Nalli ◽  
Everette Joseph ◽  
Vernon R. Morris ◽  
Christopher D. Barnet ◽  
Walter W. Wolf ◽  
...  
Keyword(s):  
Water Vapor ◽  
Water Vapor Pressure ◽  
Satellite System ◽  
Low Earth Orbit ◽  
General Interest ◽  
Tropical Atlantic ◽  
Tropical Water ◽  
Ocean Science ◽  
Polar Satellite ◽  
Temperature Water

This paper gives an overview of a unique set of ship-based atmospheric data acquired over the tropical Atlantic Ocean during boreal spring and summer as part of ongoing National Oceanic and Atmospheric Administration (NOAA) Aerosols and Ocean Science Expedition (AEROSE) field campaigns. Following the original 2004 campaign onboard the Ronald H. Brown, AEROSE has operated on a yearly basis since 2006 in collaboration with the NOAA Prediction and Research Moored Array in the Tropical Atlantic (PIRATA) Northeast Extension (PNE). In this work, attention is given to atmospheric soundings of ozone, temperature, water vapor, pressure, and wind obtained from ozonesondes and radiosondes launched to coincide with low earth orbit environmental satellite overpasses [MetOp and the National Aeronautics and Space Administration (NASA) A-Train]. Data from the PNE/ AEROSE campaigns are unique in their range of marine meteorological phenomena germane to the satellite missions in question, including dust and smoke outflows from Africa, the Saharan air layer (SAL), and the distribution of tropical water vapor and tropical Atlantic ozone. The multiyear PNE/AEROSE sounding data are valuable as correlative data for prelaunch phase validation of the planned Joint Polar Satellite System (JPSS) and NOAA Geosynchronous Operational Environmental Satellite R series (GOES-R) systems, as well as numerous other science applications. A brief summary of these data, along with an overview of some important science highlights, including meteorological phenomena of general interest, is presented.

New Design for a Differentially Pumped Hydration Chamber for a Siemens IA

1971 ◽  
Vol 29 ◽  
pp. 44-45
Author(s):  
R. C. Moretz ◽  
G. G. Hausner ◽  
D. F. Parsons
Keyword(s):  
Electron Microscopy ◽  
Water Vapor ◽  
Electron Diffraction ◽  
Water Vapor Pressure ◽  
Biological Materials ◽  
Thin Membrane ◽  
Reliable System ◽  
System A ◽  
Water Films ◽  
Aperture Opening

Electron microscopy and diffraction of biological materials in the hydrated state requires the construction of a chamber in which the water vapor pressure can be maintained at saturation for a given specimen temperature, while minimally affecting the normal vacuum of the remainder of the microscope column. Initial studies with chambers closed by thin membrane windows showed that at the film thicknesses required for electron diffraction at 100 KV the window failure rate was too high to give a reliable system. A single stage, differentially pumped specimen hydration chamber was constructed, consisting of two apertures (70-100μ), which eliminated the necessity of thin membrane windows. This system was used to obtain electron diffraction and electron microscopy of water droplets and thin water films. However, a period of dehydration occurred during initial pumping of the microscope column. Although rehydration occurred within five minutes, biological materials were irreversibly damaged. Another limitation of this system was that the specimen grid was clamped between the apertures, thus limiting the yield of view to the aperture opening.

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